Adaptive optimization process for ultrasonic measurement signals

• US 5,883,309 A
• Filed: 09/11/1997
• Issued: 03/16/1999
• Est. Priority Date: 03/15/1995
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Vossiek, Martin, Eccardt, Peter-Christian
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US08/913,691
• Time in Patent Office: 551 Days
• Field of Search: 73/602, 73/1.82, 73/632, 73/642, 73/629, 702/39, 702/103
• US Class Current: 73/602
• CPC Class Codes: B06B 1/0261 taken from a transducer or electrode connected to the driving transducer
• CPC Class Codes: G01N 29/34 Generating the ultrasonic, sonic or infrasonic waves , e.g. electronic circuits specially adapted therefor
• CPC Class Codes: G01N 29/346 with amplitude characteristics, e.g. modulated signal
• CPC Class Codes: G01N 29/40 by amplitude filtering, e.g. by applying a threshold or by gain control
• CPC Class Codes: G01N 29/50 using auto-correlation techniques or cross-correlation techniques
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205
• CPC Class Codes: G01S 7/524 Transmitters

Abstract

In order to optimize an ultrasound measurement signal application-specifically, an error value is formed from features with which an evaluation of the received ultrasound measurement signal is possible. An ultrasound signal, whose signal shape is modified by section-by-section variation of the shape of the transmission signal is emitted out, received and an error value is formed anew. This procedure is repeated until the error value assumes a minimum. The ultrasound measurement signal at which the error value is minimal corresponds to the optimized signal.

Claims

1. A method for adaptively optimizing an ultrasound measurement signal emitted by an ultrasound transducer, comprising the steps of:

(a) exciting a transmitting ultrasound transducer with a transmission signal, said transmission signal exhibiting a signal curve comprising a plurality of successive sections, and thereby causing said transmitting ultrasound transducer to emit an emitted ultrasound signal which produces a reflected ultrasound signal;

(b) receiving said reflected ultrasound signal with a reception ultrasound transducer as a received ultrasound signal, said received ultrasound signal having at least one feature representing a deviation of said emitted ultrasound signal from a predetermined optimum signal;

(c) evaluating said received ultrasound signal to obtain an initial error value dependent on said at least one feature;

(d) modifying a section of said transmission curve to obtain a modified transmission curve and exciting said transmission ultrasound transducer with said modified transmission curve to emit a new emitted ultrasound signal, which produces a new reflected ultrasound signal;

(e) receiving said new reflected ultrasound signal as a new received ultrasound signal, said new received ultrasound signal also having said at least one feature;

(f) evaluating said new received ultrasound signal to obtain a new error value dependent on said at least one feature in said new received ultrasound signal;

(g) comparing said initial error value and said new error value and updating said transmission signal if said new error value is less than or equal to said initial error value, and repeating steps (d), (e) and (f) for said section if said new error value is larger than said initial error value; and

(h) repeating steps (d) through (g) for all of said sections.

2. A method as claimed in claim 1 comprising the additional step of using a single ultrasound transducer as said transmitting ultrasound transducer and as said reception ultrasound transducer.

3. A method as claimed in claim 1 wherein step (d) comprises modifying a section of said transmission curve in successively smaller steps until a step width falls below a predetermined threshold.

4. A method as claimed in claim 1 wherein steps (b) and (e) are further defined by using an area defined by an envelope respectively of said received ultrasound signal and said new received ultrasound signal, as said feature.

5. A method as claimed in claim 1 wherein steps (b) and (e) are further defined by using an amplitude maximum respectively of said received ultrasound signal and said new received ultrasound signal, as said feature.

6. A method as claimed in claim 5 wherein step (c) is further defined by forming said initial error value as a quotient of an area defined by an envelope of said received ultrasound signal and said amplitude maximum of said received ultrasound signal, and wherein step (f) is further defined by forming said new error value as a quotient of an area defined by an envelope of said new received ultrasound signal and said amplitude maximum of said new received ultrasound signal.

7. A method as claimed in claim 1 wherein steps (b) and (e) are further defined by using a slope of a signal excerpt respectively of said received ultrasound signal and said new received ultrasound signal as said feature, for optimizing build-up time of said emitted ultrasound signal.

8. A method as claimed in claim 1 wherein steps (b) and (e) are further defined by using an amplitude maximum respectively of said received ultrasound signal and said new received ultrasound signal as said feature, for optimizing build-up time of said emitted ultrasound signal.

9. A method as claimed in claim 8 wherein step (b) is further defined by forming said initial error value as a reciprocal of a product of said amplitude of said received ultrasound signal and a slope of a signal excerpt of said received ultrasound signal, and wherein step (f) comprises forming said new error value as a reciprocal of a product of said amplitude of said new received ultrasound signal and a slope of a signal excerpt of said new received ultrasound signal.

10. A method as claimed in claim 1 comprising the additional step of overlaying said transmission signal with white noise having a noise power, and reducing said noise power of said white noise for each repetition of steps (d), (e) and (f) in step (g).

11. A method as claimed in claim 1 comprising the additional step of discretizing said received ultrasound signal and said new received ultrasound signal.

12. A method as claimed in claim 1 comprising the additional step of forming an envelope of said received ultrasound signal and said new received ultrasound signal.